Valve-gear for engines.



Patented Nov. 4, I902.

J. VORRABER. VALVE GEAR FOR ENGINES.

(Application flied may 15, 1902.

2 sheets-shut (No Model.)

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No. 712,744. Patented Nov'. 4, 1902.

.l. VORBABER. VALVE GEAR FOR ENGINES. (Application flied. May 15, 1902.(No Model.) 2 Shuts-Sheet 2.

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"JOSEF VORRABER, or scHoNINcEN, GERMANY.

VALVE-G EAR FOR ENGINES.

SPECIFICATION forming part of Letters Patent No. 712,744, dated November4, 1902.

Application filed May 15, 1902.

schweig, Germany, have invented certain new and useful Improvements inValve-Gear for Steam and Similar Power Engines o f which the followingis a specification.

The present invention relates to that class of valve-gears in which avalve-shaft, coupled to the main shaft and rotating at the same speed asthe latter, opens the valves by means of cams and levers in such amanner that a boss on a lever raises the valve-rod when the lever-armcarrying the said boss ascends and is disengaged by the governor orregulator by means of another lever when said' governor ascends, so thatthe valve is immediately closed again. v

The object of the invention is to render it possible to use this systemof valve-gear in connection with which the valve is not to fall back toits end position when the governor ascends, but only to its middleposition, in order to prevent the immediate exhaust of p the steam.

It is also the purpose of the invention to secure the most advantageousdistribution of steam, so that at the steam-inlet side the openingposition of the valve remains constant, and all charges from naught toseventy per cent. can be obtained, whereas the commencement ofcompression can take place at from eighty to eighty-six per cent, sothat from fourteen to twenty per cent. compression is obtained. Thefirst-named purpose is obtained by arranging loosely on the valve-Figure 1 is a cross-section of the steam-cylinder and one form of thevalve-gear, and

Serial No. 107,517. (No model.)

Fig. 2 is an end'view of the cam belonging to this form. 'Fig. 3 is aside elevation of the same cam on a larger scale. Fig. 4 is acrosssection of the steam-cylinder and the other form of valvegear, andFig. 5 is a longitudinal'section of the inlet-port of the cylinder shownin Fig. 4.

As shown in Figs. 1 to 3, in the first form of construction avalve-shaft e is arranged parallel to the cylinder-axis and driven inthe known manner from the crank-shaft by bevel-wheels of equal size. Tothis shaft 6 two camsf are keyed at an angle of one hundred'and eightydegrees to each other and provided with a curve as for the steam-inletand another curve y for the exhaust. Above each cam a double fork 19,provided with rollersr and r, isarranged-that is to say, the partpterminates in a four-legged frame 10',

' which has the form of a fork, both in the direction of the axis of theshaft and in the direction perpendicular to the said axis. In the upperpart of this frame the roller 7" is revolubly arranged in the lower partof the roller r, so that 0 runs on the curve as, and r on the curve y. Alever Z is pivoted to the stem of the fork p and carries a boss 8,provided with tappets which operate the valve. The said lever 1 consistsof two parallel flat bars, between which the collar n on the valve-rod 0passes and the boss 5 is pivoted. The said collar 11 is provided withprojections n and n at its upper and lower part, respectively. When thevalve-rod o is moved upward, the tappet s on the boss 8 bears againstthe projection n, and when the valve-rod is moved downward the tappet 8also on the boss 8, bears against the projection 71?.

. The regulator adjusts the shaft 'Lt, to which the lever 70 is fixed,and when the lever Z is moved upward the adj ustment-screw Z) is broughtinto contact with the arm t on the boss 8 by means of the connecting-rodo and the lever w, so that the tappet s on the boss 8 is removed fromthe projection n of the collar n. At the same moment the valve 01 ismoved downward by the pressure of the outer spring m on the piston q.Inertia and gravity would cause the valve to descend to its lowestposition, since the air-piston q is only mounted loosely on the rod 0,and the steam just admitted to the cylinder through I sition isprevented by the fact that the outer spring m, the upper end of whichbears against the upper edge of the spring-box h, presses the piston qtightly against the seat g, while the inner spring a, one end of whichbears against the piston q and the other against the before-mentionedflange z, pulls the sleeve 0' on the piston-rod 0 tightly against theunder side of the piston g. This method of suspending the valve-rod 0 inthe springcase 7t still allows of the valve being moved by the camfintoits lowest or exhaust position and its highest or inlet position, thelatter of course only when the screw 1) is sufficiently raised by theregulator.

For the low-pressure cylinder of a compound engine and the intermediatecylinder of a triple-expansion engine the screwb may be arranged on afixed arm, and the charge of the cylinder can be regulated by screwingit up or down.

The commencement and end of each of th curves as and y are so arrangedthat at the end of the cylinder at which steam is to enter the openingposition of the valve remains constant, since while the roller 7 ismoving on the ascending curve :20 all charges from nothing to seventyper cent. can be obtained, according to the position of the screw 1).The curve 3/ being concentric with the shaft e allows of the openingposition of the valve remaining constant, and, on the other hand, thecurve y of that cam f which moves the valve at the other end of thecylinder allows of arranging the commencement of compression at fromeighty to eighty-six per cent., so that fourteen to twenty per cent.compression can take place.

In the form of the apparatus represented in Figs. 4 and 5 the sameeffect is obtained by means of only one camf, and the forked frame 13can be replaced bya simple parallelogram of levers 2 3 4. Even the lever3, the roller r, and the rod 4: can be dispensed with if the camf is cutaway parallel to the curve a: and the roller 1' is caused to travel onthe lower curve thus formed. The valve is in the case illustratedarranged on top of the cylinder, but can equally well be placedunderneath the latter and is moved by the camfin the reverse sense-thatis to say, to admit steam the valve moves downward and to open theexhaust-port the valve moves upward. By this arrangement the valve d canbe caused to automatically return to its central position after acompleted period. For this purpose the one-armed lever 1, shown in thefirst form of construction, is replaced by a doublearmed lever Z, andthe valve-rod 0 is provided with two air-bufier pistons q and y, actingin opposite directions. The valve (1 is not in this case moved into theexhaust position by the projection s of the boss 3, but by the roundedend aof the leverl itself-- that is to say, said end a lifts thevalve-rod until the port 1' communicates with the passagej and theexhaust steam can pass out. (See also Fig. 5.) In the meantime thepiston y of the valve-rod 0 moves the piston q and the latter compressesthe spring on. When the stroke is completed, the spring at moves thevalve 01 back into its middle position, moving the lever Z and liftingthe rods 2 4 3. As soon as the camflifts the roller 1' the tappet s onthe boss 8 depresses thecollar n on the valve-rod 0, so that thesteamports 1' t" t are put into communication with each other and steamcan enter the cylinder. (See also Fig. 5.)

The shaft it, connected with the regulator, is in this case arranged inthe hollow pivot 5 of the lever 3 and transmits the movement given it bythe regulator to the adjustable screw 1) by means of the lever 70, therod 12, and the lever w, as in the previous form of construction. Thesaid screw is in this case arranged in vertical guides and abuts againstthe arm 15 of the boss 5 when the regulator moves upward, as in thepreviously-described construction, but not when the lever Z, carryingthe boss 3, ascends, but when it descends.

What I claim is, in a valve-gear- 1. The combination with a cylinder,pistonvalve and valve-rod, of a. valve-shaft, a cam mounted on saidshaft, a. train of levers operated by said cam, a stop controlled by theregulator, a device carried by one of the levers of the train againstwhich the stop abuts during the period of inlet, means for controllingthe piston-valve, so that on release of the aforesaid stop the valve canonly move into its middle position, and means for moving the valve toexhaust position, substan* tially as described for the purpose setforth.

2. The combination with acylinder, pistonvalve and valve-rod, of avalve-shaft, a cam mounted on said shaft and provided with a curve ofprogressively-increasing radius a train of levers operated by said cam,a boss provided with tappets and carried by one of the levers of thetrain, a stop controlled by the regulator against which one of saidtappets abuts during the period of inlet, means for controlling thepistou-valve so that on release of the aforesaid boss by the regulator,the valve can only move into its middle position, and means for movingthe valve to exhaust position substantially as described for the purposeset forth.

3. The combination with a cylinder, pistonvalve and valve-rod, of avalve-shaft, a cam mounted on said valve -shaft, having two curves sideby side, one of which is concentricfiithjhe valve-shaft and the otherhas a progressively-increasing radius, a train of levers operated bysaid cam, a boss provided with tappets and carried by one of the leversof the train, a stop controlled by the regulator against which one ofsaid tappets abuts during the period of inlet, means on the valve-rodadapted to control the piston-valve, so that on release of the aforesaidboss by the regulator the valve can only move into its middle positionand means for moving the valve to exhaust position, substantially asdescribed for the purpose set forth.

4. The combination with a cylinder, pistonvalve and valve-rod, of avalve-shaft, a cam mounted on said valve-shaft, and having two curvesside by side, one of which is concentric with the valve-shaft and theother has a progressively-increasing radius, a train of levers operatedby said cam, a boss provided with tappets and carried by one of thelevers of the train, a stop controlled by the regulator, against whichone of said tappets abuts during the period of inlet, twooppositelyacting springs mounted on the valve-rod and adapted to controlthe piston-valve, so that on release of the aforesaid boss by theregulator the valve can only move into its middle position, and aprojection on the valve-rod adapted to be engaged by another of thetappets for moving the valve to exhaust position, substantially asdescribed and for the purpose set forth.

5. The combination with a cylinder, pistonvalve and valve-rod, of avalve-shaft, a cam mounted on said valve-shaft, and having two curvesside by side, one of which is concentric with the valve-shaft and theother has a .progressively-increasing radius, a train of levers operatedby said'cam, a boss provided with tappets and carried by one of thelevers of the train, a stop controlled by the regulator, against whichone of said tappets abuts during the period of inlet, two oppositely-

